This invention relates to electric vacuum cleaners of a type that is moved across the floor on wheels and includes an external debris collecting porous bag that is considerably larger than the assembled motor, motor driven fan and pickup nozzle of the vacuum cleaner.
The general type of vacuum cleaner in question is disclosed in U.S. Pat. No. 1,843,901 issued Feb. 2, 1932 to L. W. Pardee for an Electric Suction Cleaner. The aforesaid '901 patent describes a device in which the fan impeller rotates in a vertical plane, being driven by a motor having a horizontal output shaft. Other vacuum cleaners of the type illustrated in the '901 patent have impellers that rotate in a horizontal plane, being driven by an electric motor having a vertical output shaft. The latter type of fan arrangement is illustrated in U.S. Pat. No. 1,995,630 issued Mar. 26, 1935 to R. Bass for an Electrically Operated Vacuum Cleaner.
Vacuum cleaners of the type illustrated in the '901 patent are provided with relatively large external debris collecting bags. When the bag is loaded with heavy material, the vacuum cleaner becomes relatively unstable, especially with the bag full and the vacuum cleaner at rest. This unstable condition results when the center of gravity of the device, including the debris laden collection bag, shifts considerably to the rear of the load bearing wheels which support the vacuum cleaner. In an effort to alleviate this tendency toward instability, the device of the '901 patent is provided with load bearing wheel means that are widely spaced in the front to rear direction. This serves to interfere with turning the vacuum cleaner while it is in operation, the spacing between ground and the nozzle inlet varies considerably, and if the vacuum cleaner is not on level ground it will roll easily when not being used.